This invention relates to an apparatus for compressing vessels filled with miscellaneous combustible and incombustible solid waste so as to reduce their volume, and more particularly to an apparatus for pressing various solid waste packed into cylindrical vessels, for example, steel drums, so as to reduce their volume in three dimensional directions by uniaxial compression to form reduced volume compacted blocks.
In general, miscellaneous combustible and incombustible solid waste having various shapes and properties are treated by incineration or are compressed to form compacted blocks according to their properties and thereafter are used for reclamation or are again utilized if useful substances are included. Among this solid waste, however, there are some kinds of waste unavoidably stored in places or plants where they are produced because it is impossible to dispose of them, such waste being contaminated by radioactive materials derived from nuclear power installations such as nuclear power stations, nuclear power research installations, nuclear fuel treating installations, nuclear power reprocessing factories, radioisotope treating installations and the like (which will be referred to hereinafter as "radioactive waste"), and waste contaminated by poisonous or toxic substances derived from poisonous material producing or treating processes (which will be referred to hereinafter as "poisonous waste"). In this case, they are usually packed and stored in cylindrical vessels such as steel drums in order to prevent the radioactive or poisonous substances from spattering from the waste and to prevent spread of contaminated areas. As the stored amounts progressively increase, it has been desired to treat combustible waste to reduce their volume by incinerating them in certain installations, and particularly to compress incombustible waste to reduce their volume in certain plants, at least to start studying such processes for the purpose of saving storage space.
Such a compression treatment for waste is the simplest process for reducing volume of the waste and has an advantage in that no secondary waste occurs in this process. In the compression treatment presently carried out in nuclear power stations and the like, after a lid of a steel drum is opened and waste is charged into the steel drum, the waste is compressed to reduce its volume by a press ram having a diameter slightly smaller than an inner diameter of the steel drum. With this processing, there is a risk of radioactive materials spattering to spread the contamination, and particularly, for waste having high restoring ability, the compressed waste is apt to resiliently increase again in volume, so that the expected reduction in volume cannot be achieved.
Moreover, it has been proposed to compress waste together with steel drums filled therewith to reduce their volume. In this case, the steel drum filled with waste is compressed in a cylindrical sleeve in a uniaxial direction or in three dimensional directions. In the uniaxial compression, outer diameters of compressed waste and drums (referred to hereinafter "compressed blocks") are substantially equal to or larger than inner diameter of the original steel drums, so that a new vessel having a larger inner diameter is needed for storing the compressed blocks. This is a disadvantage of the uniaxial compression. In the three dimensional compression, on the other hand, although it does not have such a disadvantage, an apparatus for compression is complicated, bulky and increases the cost of equipment due to compression in the multiple directions.
The present application is related to copending application Ser. No. 026,295 filed Mar. 16, 1987. The copending application discloses a compression and volume reduction treatment apparatus wherein a ram compresses a drum located in a large diameter sleeve through a tapered section and into a small diameter portion. The lowermost portion of the tapered sleeve has a diameter equal to the diameter of the small diameter portion. Applicants discovered that the compressed drum may jam in the small diameter portion since the diameter of the small diameter portion is equal to the smallest diameter of the lowermost portion of the tapered sleeve.